Fossil flora of Middle Jurassic Grojec clays (southern Poland). Raciborski’s original material reinvestigated and supplemented. I. Sphenophytes

Abstract

AbstractSphenopsid remains from Grojec clays (Grojec, Poręba, Mirów) collected and described by Raciborski in 1894 are re-examined for the first time and supplemented by Raciborski’s unpublished material housed at the Jagiellonian University (Institute of Botany) and by Stur’s preliminarily described material stored at the Geological Survey of Austria. Three species of Equisetum created by Raciborski (Equisetum renaulti, E. remotum, E. blandum) are now attributed to the common Jurassic species Equisetites lateralis, and the earlierundescribed Equisetites cf. columnaris is recognised. The occurrence of Neocalamites lehmannianus (originally described by Raciborski as Schizoneura hoerensis) has been confirmed from Grojec. The material that Raciborski referred to this species seems to be heterogeneous, and some specimens are now removed to the new proposed species Neocalamites grojecensis Jarzynka et Pacyna sp. nov. The new species is diagnosed by the following features: only a few prominent ribs present on shoot, leaf scars relatively large and ellipsoidal, numerous free leaves, vascular bundles alternate at node. Possibly the new species derives from Neocalamites lehmannianus or at least is closely related to it. Part of the poorly preserved remains can be determined only as Neocalamites sp. Another species created by Raciborski, Phyllotheca (?) leptoderma, is based on poorly preserved type specimens. Some of the unpublished specimens stored at the Jagiellonian University (Institute of Botany) correspond to Raciborski’s description, but considering the poor preservation of the original material and the not very realistic published illustrations of this species, they rather should be regarded as indeterminate cortical fragments of Neocalamites lehmannianus and/or badly preserved external cortical surfaces of the new species Neocalamites grojecensis. Phyllotheca (?) leptoderma should be considered a nomen dubium.